Integrated embolic protection devices

ABSTRACT

Embolic Protection elements are integrated with a catheter or access sheath for any catheter. A catheter shaft has an embolic filter slidably mounted on a distal portion of a catheter shaft. A proximal stop for limits proximal movement of the embolic filter, and a distal stop for limits distal movement of the embolic filter. The filter has a porous mesh material defining a collection chamber for captured emboli and has a collapsed and a deployed configuration. The filter may be collapsed by an access sheath used with the catheter. An access sheath may have a tubular main body and an embolic filter mounted on the distal portion of the tubular main body. The embolic filter may evert into the central lumen of the sheath or may be constrained on the exterior of the sheath with a larger diameter outer tube.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/735,864, filed Jan. 7, 2013, now U.S. Pat. No. 9,492,265, whichclaims the benefit of U.S. Provisional Application No. 61/584,094, filedJan. 6, 2012, and U.S. Provisional Application No. 61/738,852, filedDec. 18, 2012, which applications are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present disclosure relates to medical devices, systems, and methods.In particular, the present disclosure relates to apparatus, systems, andmethods for providing embolic protection in a patient's vascular system.More specifically, the present disclosure relates to embolic protectiondevices that can be deployed in a blood vessel to protect branch vesselsand downstream organs from potential emboli during a catheter-basedinterventional procedure.

2. Background of the Invention

Cerebral embolism is a known complication of cardiac surgery,cardiopulmonary bypass, catheter-based interventional cardiology andelectrophysiology procedures, and many other surgical procedures.Embolic particles, which may include thrombus, atheroma, and lipids, maybecome dislodged by surgical or catheter manipulations and enter thebloodstream, embolizing in the brain or other vital organs downstream.Cerebral embolism can lead to neuropsychological deficits, stroke, andeven death. Other organs downstream can also be damaged by embolism,resulting in diminished function or organ failure.

Prevention of embolism would benefit patients and improve the outcome ofmany surgical procedures. Many current devices for preventing cerebralembolism may be less than ideal in various respects. For example, suchcurrent devices may involve multiple components and multiple steps,making the use of such devices cumbersome and even injury-prone for thepatient. Also, when used with other catheter-based interventional tools,the patient's vasculature may need to be accessed at multiple points andthrough multiple paths. For example, a current embolic protection devicemay be advanced into the aortic arch through the descending aorta whileother catheter-based interventional tools may then need to be advancedinto or into proximity with the heart through other blood vesselsincluding the vena cava, the right common carotid artery, and the leftcommon carotid artery. Therefore, improved devices, systems, and methodsfor prevention or embolism that overcome at least some of theaforementioned short-comings are desired.

Previous devices for preventing cerebral embolism are described in thefollowing patent application and patent publications: U.S. Pub. No.2010/0312268 to Belson, entitled “Embolic Protection Device”; U.S. Pub.No. 2004/0215167 to Belson, entitled “Embolic Protection Device”; U.S.Pub. No. 2003/0100940 to Yodfat, entitled “Implantable IntraluminalProtector Device and Method of Using Same for Stabilizing Atheromoas”;PCT Pub. No. WO/2004/019817 to Belson, entitled “Embolic ProtectionDevice”; U.S. Pat. No. 6,537,297 to Tsugita et al., entitled “Methods ofProtecting a Patient from Embolization During Surgery”; U.S. Pat. No.6,499,487 to McKenzie et al., entitled “Implantable Cerebral ProtectionDevice and Method of Use”; U.S. Pat. No. 6,371,935 to Macoviak et al.,entitled “Aortic Catheter with Flow Divider and Methods for PreventingCerebral Embolization”; U.S. Pat. No. 6,361,545 to Macoviak et al.,entitled “Perfusion Filter Catheter”; U.S. Pat. No. 6,254,563 toMacoviak et al., entitled “Perfusion Shunt Apparatus and Method”; U.S.Pat. No. 6,139,517 to Macoviak et al., entitled “Perfusion ShuntApparatus and Method”; and U.S. Pat. No. 5,769,819 to Barbut et al.,entitled “Cannula with Associated Filter.”

SUMMARY OF THE INVENTION

The present disclosure provides devices, systems, and methods thatovercome at least some of the short-comings of many current embolicprotection devices discussed above. Prevention of embolism would benefitpatients and improve the outcomes of many catheter-based interventionalprocedures. Given that potential emboli are often dislodged duringcatheter-based procedures, it would be advantageous to deploy an embolicprotection system as part of a catheter-based vascular procedure oralong with the sheath that is to be used during the procedure. Theembolic protection system can be integrated on the catheter that isbeing used to perform the procedure, such as a transcatheter valvedelivery system or an electrophysiology catheter, or be integrated onthe sheath that is being used to perform the procedure, such as is usedwith a transcatheter valve delivery system or an electrophysiologycatheter. Other embolic protection systems require separate proceduralsteps for installing the protector prior to the interventional ordiagnostic procedure and removing the protector after the procedure. Inmany cases, a different access site is required as well. By having anembolic protection device integrated with the catheter or access sheath,extra procedural steps and the need for an extra access site can both beminimized. Where the embolic protection device is integrated with anaccess sheath, a conventional sheath can simply be replaced with onewith an integrated embolic protection device, minimizing the need forextra devices. Where the embolic protection device is integrated with acatheter, such integration may in many cases not increase the overalldiameter of the catheter. Also, the integrated embolic protection devicemay be mounted on the catheter with a slidable connection so that thecatheter can freely slide through the embolic protection device after ithas been deployed in a blood vessel.

An aspect of the present disclosure provides a catheter with anintegrated embolic protection device or element. The catheter comprisesa shaft, an embolic filter, and at least one of a proximal or distalstop. The catheter shaft has a lumen and a distal portion. The embolicfilter is slidably mounted over the distal portion of the shaft. Thefilter comprises a port for the passage of the shaft therethrough and aporous mesh material. The porous mesh material defines a collectionchamber for captured emboli. The filter has a collapsed configurationand a deployed configuration. In the deployed configuration, an outerperiphery of the filter contacts a blood vessel wall to direct bloodflow and potential emboli into the collection chamber. The proximal stoplimits the proximal movement of the embolic filter on the distal portionof the shaft while the distal stop limits the distal movement of theembolic filter. A resilient seal may be positioned within the catheterport for forming a seal around the shaft passing through the filterport.

Typically, the porous mesh material will comprise a cylindrical outerportion and a conical inner portion. The conical inner portion ispositioned inside the cylindrical outer portion and has a wider proximalend joined to the cylindrical outer portion and a narrow distal endcoupled to the shaft passage port. The distal end of the embolic filteris open for blood to flow between the conical inner portion and thecylindrical outer portion. The space between the conical inner portionand the cylindrical outer portion defines the collection chamber forcaptured emboli.

Typically, a stent-like support scaffold will be coupled to thecylindrical outer portion of the porous mesh material for supporting thecylindrical outer portion. The stent-like support scaffold can have acollapsed configuration and an expanded configuration. The stent-likesupport scaffold self-expands into the expanded configuration when thefilter is in the deployed condition. The stent-like support scaffold maybe made of a resilient metal, polymer material, a malleable material, aplastically deformable material, a shape-memory material, orcombinations thereof.

The catheter may further comprise structures to facilitate the collapseof the embolic filter back into the collapsed configuration afterdeployment. The catheter may comprise a pull loop or other graspablestructure coupled to the distal end of the cylindrical outer portion forclosing the collection chamber. At least one retraction member may becoupled to the cylindrical outer portion for facilitating the retractionof the embolic filter into the undeployed configuration.

In some cases, the cylindrical outer portion comprises at least onecloseable side port for the introduction of a second catheter,guide-wire, delivery sheath, or other surgical tool therethrough. Thisside port can be useful for operations where the use of multiplecatheters or interventional tools is required and embolic protection isstill desired.

The porous mesh material of the embolic filter can have many properties.It may have a collapsed configuration and an expanded configuration. Itmay self-expand into the expanded configuration when it is in thedeployed configuration. It may comprise a fabric of knitted, woven, ornonwoven fibers, filaments, or wires having a pore size chosen toprevent emboli over a predetermined size from passing through. It may bemade of a resilient metal, polymer material, or combinations thereof, amalleable or plastically deformable material, or a shape-memorymaterial. It may have an antithrombogenic coating on its surface. It mayhave a pore size in the range of about 1 mm to about 0.1 mm to preventemboli above a certain size from passing through while allowing thepassage of blood.

The shaft passage port of the embolic filter may be configured to form aseal to prevent passage of emboli over a predetermined sizetherethrough.

The embolic filter may be slidably mounted on the distal portion of theshaft in many ways. The distal portion of the shaft may comprise alow-profile portion over which the embolic filter is slidably mounted.In this case, the proximal stop may comprise a proximal end of thelow-profile portion and the distal stop may comprise a distal end of thelow-profile portion. Alternatively or in combination, the proximal stopmay comprise a proximal stop member and the distal stop may comprise adistal stop member, with both stop members being attached or otherwisecoupled to the distal portion of the shaft. In some cases, theseproximal and distal stops may be integral with the catheter shaft.

At least one of the shaft, embolic filter, proximal stop, or distal stopmay be radiopaque or comprise a radiopaque marker to facilitate theviewing of the catheter and its parts during a surgical procedure.

The catheter can be inserted through a tubular outer delivery sheath.The tubular outer delivery sheath maintains the embolic filter in theundeployed retracted condition when the embolic filter is therewithin.The embolic filter will be free to deploy into the deployed expandedconfiguration when the embolic filter is advanced out of the tubularouter delivery sheath.

The distal end of the shaft may be coupled to a valve replacementdelivery element, an expandable structure for balloon valvuloplasty, anenergy delivery element for ablation, or other transcatheter surgicalelement.

Another aspect of the present disclosure provides a system forcatheter-based interventional procedures. The system comprises thecatheter described above and a tubular outer delivery sheath throughwhich the catheter is advanced.

Yet another aspect of the present disclosure provides an introducersheath with an integrated embolic protection device or element. Thisintroducer sheath can be used for the delivery of surgical instrumentsand comprises a tubular member and an embolic filter. The tubular memberhas a central lumen and a distal portion. The embolic filter is coupledto the distal portion of the shaft. The filter comprises a porous meshmaterial defining a collection chamber for captured emboli. The filterhas a collapsed configuration and a deployed configuration. In thedeployed configuration, an outer periphery of the filter contacts ablood vessel wall to direct blood flow and potential emboli into thecollection chamber.

The embolic filter can be collapsed or constrained in many ways. In oneexample, the embolic filter is coupled to an exterior of the distalportion of the tubular member and is collapsed into the collapsedconfiguration by an exterior constraining member. The exteriorconstraining member may be a tube slidable over the tubular member. Inanother example, the embolic filter is collapsed by retraction of thefilter into the central lumen of the tubular member. Here, the embolicfilter is coupled to an internal tube or wire structure disposed in thecentral lumen of the tubular member for retraction of the embolic filterinto the central lumen.

Typically, the porous mesh material comprises a cylindrical outerportion and a conical inner portion. When the embolic filter is in thedeployed configuration, the conical inner portion is positioned insidethe cylindrical outer portion. The conical inner portion has a widerproximal end joined to the cylindrical outer portion and a narrow distalend coupled to the distal portion of the tubular member. The distal endof the embolic filter is open for blood to flow between the conicalinner portion and the cylindrical outer portion. The space between theconical inner portion and the cylindrical portion defines the collectionchamber for captured emboli.

The sheath may further comprise a stent-like scaffold coupled to thecylindrical outer portion of the porous mesh material for supporting thecylindrical outer portion. It may have a collapsed configuration and anexpanded configuration, and may self-expand into the expandedconfiguration when the filter is in the deployed condition. It may bemade of a resilient metal, polymer material, a malleable material, aplastically deformable material, a shape-memory material, orcombinations thereof.

The introducer sheath may include further structures to facilitate thecollapse of the embolic protection element. The sheath may furthercomprise a pull loop or other graspable structure coupled to the distalend of the cylindrical outer portion for closing the collection chamber.The sheath may further comprise at least one retraction member coupledto the cylindrical outer portion for facilitating the retraction of theembolic filter into the undeployed configuration.

In some cases, the cylindrical outer portion may comprise at least onecloseable side port for the introduction of a second catheter,guide-wire, delivery sheath, or other surgical tool therethrough.

The porous mesh material of the embolic filter can have many properties.It may be made of a resilient metal, polymer material, a malleablematerial, a plastically deformable material, a shape-memory material, orcombinations thereof. It may have an antithrombogenic coating on itssurface. It may have a pore size in the range of about 1 mm to about 0.1mm.

At least one of the tubular member or embolic filter may be radiopaqueor comprise a radiopaque marker.

Yet another aspect of the present disclosure provides a system forcatheter-based interventional procedures. The system comprises the abovedescribed introducer sheath and a catheter deliverable through thecentral lumen of the introducer sheath. The catheter can be coupled to avalve replacement delivery element, an expandable structure for balloonvalvuloplasty, an energy delivery element for ablation, or othertranscatheter surgical element.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the disclosure are set forth with particularity inthe appended claims. A better understanding of the features andadvantages of the present disclosure will be obtained by reference tothe following detailed description that sets forth illustrativeembodiments, in which the principles of the disclosure are utilized, andthe accompanying drawings of which:

FIG. 1A is a side view of a catheter with an integrated embolicprotection device according to an embodiment of the invention;

FIG. 1B is a cross-sectional view of the catheter of FIG. 1A;

FIG. 1C is a side cross-sectional view of a catheter with an integratedembolic protection device according to another embodiment of theinvention;

FIG. 1D is a side cross-sectional view of a catheter with an integratedembolic protection device according to yet another embodiment of theinvention;

FIG. 1E is a side cross-sectional view of a catheter with an integratedembolic protection device according to yet another embodiment of theinvention;

FIGS. 2A to 2D show a catheter-based interventional procedure using acatheter with an integrated embolic protection device according toembodiments of the invention;

FIG. 3A is a side cross-sectional view of an access sheath with anintegrated embolic protection device according to an embodiment of theinvention;

FIG. 3B is a side cross-sectional view of an access sheath with anintegrated embolic protection device according to another embodiment ofthe invention;

FIG. 3C is a side cross-sectional view of an access sheath with anintegrated embolic protection device according to yet another embodimentof the invention; and

FIG. 3D is a side cross-sectional view of an access sheath with anintegrated embolic protection device according to yet another embodimentof the invention.

DETAILED DESCRIPTION OF THE INVENTION

Aspects of the disclosure provide improved devices, systems, and methodsfor the prevention of embolisms in a catheter-based interventionalprocedure. In particular, catheters and sheaths with integrated embolicprotection devices or elements are provided. Various aspects of thedisclosure described herein may be applied to any of the particularapplications set forth below or for any other types of catheter oraccess sheath for catheters. It shall be understood that differentaspects of the disclosure can be appreciated individually, collectively,or in combination with each other.

1. Catheter with Integrated Embolic Protection Device

According to an aspect of the present disclosure, a catheter for acatheter-based interventional procedure can itself be provided with anintegrated embolic protection device or element. FIG. 1A is a side viewof a catheter 100 with an integrated embolic protection device orelement 110. The integrated embolic protection device or element 110 isshown in its deployed configuration in FIG. 1A. The catheter 100 may beadvanced into a surgical site through delivery sheath SH. The integratedembolic protection element 110 has a collapsed configuration when it isconstrained by delivery sheath SH. The embolic protection element 110 isallowed to expand into the deployed configuration when it is advancedout of the distal end of the delivery sheath SH. For example, at least aportion of the integrated embolic protection element 110 may beself-expanding and self-supporting.

The catheter 100 may optionally include a shoulder positioned proximalto the embolic protection element 110 to maintain the position of theembolic protection element 110 on the catheter 100 as the deliverysheath SH is withdrawn during deployment. Alternatively, a pushercatheter that fits in-between the catheter 100 and the delivery sheathSH may be used to facilitate deployment.

The catheter 100 comprises a catheter shaft 105 that the integratedembolic protection element 110 is mounted over. The integrated embolicprotection element 110 comprises a porous mesh material 111, which actsas a filter. The porous mesh material 111 comprises two main sections, acylindrical outer structure 115 and a conical inner structure 120. Thecylindrical outer structure 115 is deployed adjacent to the blood vesselwall to protect branch vessels. The central conical inner structure 120is deployed within the center of the vessel lumen to provide protectionto downstream circulation. An upstream or distal end 130 of the embolicprotection element 110 opens into a space between the cylindrical outerstructure 115 and the conical inner structure 120. This space defines anembolic collection chamber 135 for capturing emboli.

The catheter 100 may be configured as a diagnostic catheter, a guidingcatheter, or a therapeutic catheter. As shown in FIG. 1A, the distal endof the catheter shaft 105 will typically be coupled with aninterventional element 145. The interventional element 145 may comprisea cardiac valve replacement implant delivery device, an expandablestructure for balloon valvuloplasty, an energy delivery element forablation, or any number of other structures for catheter-based surgery,implantation, electrophysiological procedures, or other procedures.

The integrated embolic protection element 110 comprises a port 140,which is coupled to the distal portion of the shaft 105. As shown inFIG. 1A, the port 140 is coupled to a distal or upstream end of theconical inner structure 120. The port 140 is sealed tight enough againstthe shaft 105 so that no emboli may pass through the space between theport 140 and the shaft 105. In some embodiments, the integrated embolicprotection element 110 will be fixedly mounted on the distal portion ofthe catheter shaft 105. Typically, the integrated embolic protectionelement 110 will be slidably mounted over the distal portion of thecatheter shaft 105. The shaft 105 may further comprise a downstream orproximal stop 150 which limits proximal movement of the embolicprotection element 110 on the shaft 105 and an upstream or distal stop155 which limits distal movement of the embolic protection element 110on the shaft 105.

The porous mesh material 111 may be made of knitted, woven, or non-wovenfibers, filaments or wires and will have a pore size (e.g., from about 1mm to about 0.1 mm) chosen to allow blood to pass through but preventemboli above a certain size from passing through. The porous meshmaterial may be made of a metal, a polymer, or a combination thereof andmay optionally have an antithrombogenic coating on its surface (e.g.,the porous mesh material 111 may be heparinized).

The embolic protection element 110 will preferably be self-supporting inthe deployed configuration. In some embodiments, the porous meshmaterial 110 may be made of a shape-memory material so that it mayself-expand when no longer constrained by sheath SH and collapse into alow-profile configuration when constrained by sheath SH. The embolicprotection element 110 will also preferably maintain sufficient contactwith the target vessel wall to form an adequate seal to prevent emboliabove a certain size from passing around the outside of the embolicprotection element 110.

Typically, the cylindrical outer structure 115 will be supported by astent-like support structure 160. The stent-like support structure 160provides support to the porous mesh material 110 and maintains anadequate seal against the vessel wall. The stent-like support structure160 may comprise a framework that includes one or more longitudinalstruts and hoops that form the support structure 160. The hoops andstruts may be made of a shape memory material so that it may self-expandwhen no longer constrained by sheath SH and collapse into a low-profileconfiguration when constrained by sheath SH. Alternatively, the hoopsand struts may be made of a resilient metal and/or polymer material tomake a self-expanding framework or a malleable or plastically deformablematerial to make a framework that can be expanded with an inflatableballoon or other expansion mechanism. The porous mesh material 110supported on the framework can be resilient, flaccid, or plasticallydeformable. Hybrid constructions that combine features of theself-supporting structure and the frame-supported structure may also beused. Hybrid deployment methods, such as balloon-assisted self-expansioncan also be utilized.

In some embodiments, the stent-like support structure 160 may comprise aside port 161 through which a second catheter or other interventionaldevice may be passed through to access a surgical site. The side port161 may be collapsible and closeable so that no emboli passed throughthe side port 161 when it is not being used. Alternatively, the porousmesh material 110 and the stent-like support structure 160 may beresilient enough so that a second catheter or other interventionaldevice may be passed through its pores to access a surgical site withoutpermanently affecting the pore sizes of the aforementioned structures.

FIG. 1B is a cross-sectional view of the catheter 100 taken along line1B in FIG. 1A. As shown in FIG. 1B, the support structure 165 is coupledto the cylindrical outer structure 115. The catheter shaft 105 comprisesa central lumen 165, and the port 140 comprises a sliding mechanism 170.The catheter 100 may be delivered with the embolic protection element110 in the undeployed or collapsed configuration over a guide-wiredisposed within the central lumen 165.

In many embodiments, the sliding mechanism 170 need not make a perfecthemostatic seal. Preferably, the sliding mechanism 170 should excludethe passage of emboli above a certain size therethrough. The slidingmechanism 170 can comprise one or more rings, roller bearings, or otherstructures that allow the embolic protection element 110 to slide freelyon the catheter shaft 105. The sliding mechanism 170 will preferablyhave a low coefficient of friction and/or a lubricious coating so thatmovement of a catheter shaft 105 through the sliding mechanism 170 willnot jostle or dislodge the embolic protection element 110. Inalternative embodiments, the sliding mechanism 170 can contain anadditional sealing element, such as resilient flaps, an iris structure,an expandable sealing material, or the like.

FIG. 1C is a side cross-sectional view of a catheter 100 a that isgenerally similar to the catheter 100 described above. In catheter 100a, the integrated embolic protection device 110 is mounted over alow-profile section 105 a of catheter shaft 105 to minimize the overalldiameter or “profile” of the collapsed embolic protection device 110 andcatheter shaft 105. The catheter shaft 105 can comprise a downstream orproximal transition point 151 where the shaft 105 transitions fromhaving a low-profile to having a normal profile. This transition point151 can act as a downstream or proximal stop 151 to limit the proximalmovement of the integrated embolic protection device 110. Likewise, thecatheter shaft 105 can further comprise an upstream or proximaltransition point 156 which can act as an upstream or distal stop 156 tolimit the distal movement of the integrated embolic protection device110.

As shown in FIG. 1C, the sliding mechanism 170 may be attached to thereduced diameter section 105 a of the catheter shaft 105. Preferably,the diameter of the undeployed embolic protection element 110 whenretracted onto the reduced diameter section 105 a will be no larger thanthe largest section of the catheter 100, which will typically be theregion of the interventional element 145 at the distal end of thecatheter shaft 105. Downstream or proximal of the interventional element145, the catheter shaft 105 can be reduced in size to allow integrationof the embolic protection element 110 without changing the overalltracking profile of the catheter 100. In some embodiments, the overalltracking profile of the catheter 100 may be as small as 8 to 9 French oreven smaller.

As shown in FIG. 1A, the wider end of the conical inner structure 120 ison the proximal or upstream side. Alternatively, the wider end of theconical inner structure 120 may be on the distal or upstream side asshown in FIGS. 1C to 1E.

The embolic protection element 110 can be retracted and withdrawn withthe catheter shaft 105 after the desired diagnostic or interventionalprocedures has been completed. In many embodiments, the catheter 100includes features to assist in retracting the device for retrieval froma target site such as the patient's aorta. Examples of such features areshown in FIGS. 1D and 1E.

FIG. 1D is a side cross-sectional view of a catheter 100 b that isgenerally similar to catheter 100 a described above. The catheter 100 bfurther comprises a conical guiding structure 185, which is slidablycoupled to the catheter shaft downstream of or proximal to the embolicprotection element 110 with a sliding mechanism 190. The conical guidingstructure 185 may comprise one or more curved arms coupling the outercylindrical structure 115 and/or the stent-like support structure 160with the catheter shaft 105. In some embodiments, the conical guidingstructure 185 may be integral with the stent-like support structure 160,i.e., the stent-like support structure 160 may comprise a cylindricalupstream or distal portion and a conical downstream or proximal portionthat acts as a conical guiding structure. The conical guiding structure185 assists the embolic protection element 110 in collapsing when thesheath SH is advanced along the conical guiding structure 185. In someembodiments, the upstream or distal end of the conical guiding structure185 may be coupled to the outer cylindrical structure 115 and/or thestent-like support structure 160, and gradual distal advancement of thesheath SH will cause the conical guiding structure 185 to graduallycollapse the embolic protection element 110.

FIG. 1E is a side cross-sectional view of a catheter 100 b that isgenerally similar to catheter 100 a described above. The catheter 100 bfurther comprises tethers 195. The tethers 195 may be made of suture,wire, plastic filament, or a combination thereof. The tethers 195 aredisposed within a circumferential loop of the porous mesh material atthe upstream or distal end of the outer cylindrical structure 115. Thetethers 195 lead back into the sheath SH where they can be pulled backby a user at the user end of the sheath SH. The tethers 195 can act asdrawstrings to close the upstream or distal end of the outer cylindricalstructure 115, thereby closing off the emboli collection chamber 135. Itmay be desirable to first close off the emboli collection chamber 135 toseal any emboli and potential emboli inside before the embolicprotection element 110 is retracted into the sheath SH. This initialsealing can assure that any captured emboli do not migrate out of theembolic protection element 110.

Further tethers or retraction members may be provided to similarly closeoff one or more other sections of the embolic protection element 110.The tethers or retraction members may also serve as retraction membersto facilitate the retraction and collapsing of the embolic protectionelement 110 into the sheath SH. For example, the downstream or proximalend of the cylindrical outer structure 115 may be coupled to one or moretethers or retraction members that can be retracted to reduce thecircumference of the cylindrical outer structure 115. In someembodiments, a pool loop or other graspable structure near thedownstream or proximal end of the embolic protection element 110 isconnected to the tethers or retraction members by one or more connectingmembers.

For catheters 100, 100 a, 100 b, and 100 c shown in FIGS. 1A to 1E, theembolic protection element 110 may be constructed with the porous meshmaterial 111 and the stent-like support structure 160 havingapproximately the relative longitudinal dimensions shown in thedrawings. The porous mesh material 111 and the stent-like supportstructure 160, however, can each be made longer or shorter withoutadversely affecting the performance of the embolic protection element110.

The entire catheter 100 or portions of it may be coated with ananti-thrombogenic coating, for example, a bonded heparin coating, toreduce the formation of clots that could become potential emboli.Alternatively or in addition, the entire catheter 100 or portions of itmay have a drug-eluting coating containing an anti-inflammatory orantistenosis agent. The catheter 100 with an integrated embolicprotection element 110 is described herein for protecting againstcerebral embolisms but may be used for protecting against emboli inother organ systems. For example, the catheter 100 and embolicprotection element 110 can be deployed in the patient's ascending aortafor preventing embolic particles in the aortic blood flow from enteringthe renal arteries and embolizing in the patient's kidneys.Alternatively or in addition, the entire catheter 100 or portions of itmay be radiopaque to facilitate viewing of the catheter 100 as aprocedure proceeds. Radiopaque markers may also be coupled to one ormore portions of the catheter 100.

FIGS. 2A to 2D show a catheter-based interventional procedure using thecatheter 100 with the integrated embolic protection element 110.

FIG. 2A shows the catheter 100 with the integrated embolic protectionelement 110 held in the undeployed, collapsed configuration by thesheath SH. The catheter 100 has been inserted through the descendingaorta DA so that the embolic protection element 110 within the aorticarch AA and the interventional element 145 advanced out through thesheath SH so that it is at the aortic valve AV. As shown in FIGS. 2A to2D, the interventional element 145 is an aortic replacement valvedelivery system. The catheter 100 and interventional element 145 mayalso be configured to deliver replacement valves for the mitral valve,the tricuspid valve, or the pulmonary valve. The catheter 100 and theinterventional element 145 may also be used to other procedures such asany electrophysiological procedure, balloon valvuloplasty, and variousablative procedures, among others.

As shown in FIG. 2B, the sheath SH has been retracted to allow theembolic protection element 110 to expand to contact that vessel wall ofthe aortic arch AA. The embolic protection element 110 is positioned soas to prevent emboli above a certain size from entering thebrachiocephalic artery BA, the left carotid artery CA, the leftsubclavian artery SA, and the descending aorta DA. As shown in FIG. 2B,the catheter 100 may comprise tethers 195 and the guiding structure 185,both described above, to facilitate retraction and collapsing of theembolic protection element 110. For ease of illustration, the tethers195 and the guiding structure 185 are not shown in FIG. 2A.

Once the desired interventional procedure has been performed, theembolic protection element 110 can be collapsed and the catheter 100retracted. As shown in FIG. 2C, the interventional procedure performedis the delivery of an aortic valve replacement 148. As discussed above,other interventional procedures may instead be performed. As shown inFIG. 2C, the tethers 195 are retracted to close the upstream or distalend of the embolic protection element 110.

Once the upstream or distal end of the embolic protection element 110 isclosed, the catheter shaft 105 can be retracted to begin to pull theembolic protection element 110 into the sheath SH. As shown in FIG. 2D,the conical guiding structure 185 facilitates the collapsing of theembolic protection element 110 as it is retracted. Once the cathetershaft 105, the interventional element 145, and the embolic protectionelement 110 are completely retracted into the access sheath, thecatheter 100 and the sheath SH can be complete removed from the aorticarch AA, the descending aorta DA, and the patient's body. For ease ofillustration, the tethers 195 are not shown in FIG. 2D.

2. Access Sheath with Integrated Embolic Protection Device

According to another aspect of the present disclosure, a sheath used fora catheter-based interventional procedure can itself be provided with anintegrated embolic protection device or element. FIG. 3A is a sidecross-sectional view of an access sheath 300 with an integrated embolicprotection element 305. For example, the access sheath 300 may be usedin lieu of the sheath SH used in the procedure shown in FIGS. 2A to 2Dor any other catheter-based interventional procedure. With the accesssheath 300 having an integrated embolic element 305, any catheter, notjust the catheter 100 with an integrated embolic element 110, can beused in a desired interventional procedure while enjoying the benefitsof protection against emboli with minimum extra steps and parts asdescribed in the present disclosure.

The integrated embolic protection element 305 may in many respects besimilar to the integrated embolic protection element 105 describedabove. The integrated embolic protection element 305 is coupled to thedistal end 301 of the access sheath 300 and comprises a porous meshmaterial 306. The porous mesh material 306 comprises a conical innerstructure 310 coupled to a cylindrical outer structure 320. The upstreamor distal end 315 of the conical inner structure 310 is coupled to thedistal end 301 of the access sheath 300. The proximal or downstream end316 of the conical inner structure 310 is coupled to the proximal ordownstream end 321 of the cylindrical outer structure 320. The spacebetween the conical inner structure 310 and the cylindrical outerstructure 320 defines a collection chamber 325 for capturing emboliabove a certain size.

The porous mesh material 306 may be made of a knitted, woven, ornon-woven fibers, filaments, or wires and will have a pore size chosento allow blood to pass through but prevent emboli above a certain sizefrom passing through. The porous mesh material 306 may be made of ametal, a polymer, or a combination thereof and may optionally have anantithrombogenic coating on its surface.

The embolic protection element 305 will typically be in its undeployedconfiguration in or on the main tubular body of the sheath 300 as it isinserted into a blood vessel. The embolic protection element 305 willtypically be deployed across especially critical branch vessels, such asacross the aortic arch to cover the ostia of the cerebral arteries. Theintegrated embolic protection element 305 is shown in its expanded,deployed configuration in FIG. 3A, with the cylindrical outer structure320 contacting the blood vessel wall By. When the sheath SH ispositioned, advanced, or retracted within a patient's vasculature,however, the integrated embolic protection element 305 will typicallyneed to be in its collapsed, undeployed configuration.

The integrated embolic protection element 305 may be collapsed orconstrained in many ways. For example, a larger diameter outer tube 330may be provided as shown in FIG. 3B. The larger diameter outer tube 330is disposed over the porous mesh material 306 to constrain it betweenthe outer surface of the sheath 300 and the inner surface of the largerdiameter outer tube 330. In such embodiments, the integrated embolicprotection element 305 may be self-expanding such that it can assume theshape shown in FIG. 3A when the larger diameter outer tube 330 isretracted or when the sheath 300 is advanced out of the upstream ordistal end of the larger diameter outer tube 330.

In another example, the integrated embolic protection element 305 may bestored within the interior of the sheath 300 when the embolic protectionelement 305 is in its collapsed, undeployed configuration as shown inFIG. 3C. The sheath 300 may comprise retraction element 340 coupled tothe embolic protection element 305. The retraction element 340 may be aninner tube or one or more inner arms that can be used to push theintegrated embolic protection element 305 out of the tubular main bodyof the sheath 300 or to pull it back into the sheath 300. As the embolicprotection element 305 is coupled to the distal end 301 of the sheath300, the embolic protection element 305 everts out of the main body ofthe sheath 300 when it is advanced out.

The embolic protection element 305 will preferably be self-supporting inthe deployed configuration. The embolic protection element 305 will alsopreferably maintain sufficient contact with the vessel wall to form anadequate seal to prevent emboli above a certain size from passing aroundthe outside of the embolic protection element 305. For example, theporous mesh material 306 may be constructed with a resilient filter meshmaterial that can be compressed into the undeployed configuration andwill self-expand into the deployed configuration.

As shown in FIG. 3D, the sheath 300 may comprise a stent-like supportstructure 345 similar to the stent-like support structure 160 describedabove for supporting the cylindrical outer structure 320. The stent-likesupport structure 345 may comprise a framework that includes one or morelongitudinal struts or hoops that form a support structure and assist inthe expansion and wall apposition of the embolic protection element 305.The hoops and struts may be made of a resilient metal and/or polymermaterial to make a self-expanding framework or malleable or plasticallydeformable material to make a framework that can be expanded with aninflatable balloon or other expansion mechanism. Alternatively, theframework can be made of a shape-memory material that can be used todeploy and/or retract the embolic protection element 305. The porousmesh material 306 supported on the framework 345 can be resilient,flaccid, or plastically deformable. Hybrid constructions that combinefeatures of the self-supporting structure and the frame-supportingstructure may also be used. Hybrid deployment methods, such asballoon-assisted self-expansion can also be utilized.

The integrated embolic protection element 305 is retracted and withdrawnwith the sheath 300 after the diagnostic or interventional procedure hasbeen completed. The sheath 300 may include features that facilitateretraction of the integrated embolic protection element 305 as shown inFIG. 3D. The upstream or distal end of the embolic protection element305 may be coupled to one or more tethers 350 which may form acircumferential loop therearound. Similar to the tethers 195 describedabove, the tethers 350 can be retracted to close the upstream or distalend of the embolic protection element 305 prior to retraction of thesheath 300. The tethers 350 may also be coupled to other sections of theembolic protection element to facilitate closure of the embolicprotection element 305 or retraction thereof. In some embodiments, apull loop or other graspable structure near the downstream or proximalend of the embolic protection element 305 may be connected to theretraction members or tethers 350 by one or more connecting members.

Also, the sheath 300 may further comprise a conical guiding structure360 which at the upstream or distal end be coupled to the cylindricalouter structure 320 and/or the stent-like support structure 345. At thedownstream or proximal end, the conical guiding structure 360 is coupledto the outer portion of the main tubular body of the sheath 300 with asliding mechanism 300. The conical guiding structure 360 may be similarto the conical guiding structure 185 described above, and may facilitatethe collapse of embolic protection element 305 when the larger diametertube 330 is advanced thereover.

As shown in FIG. 3D, the porous mesh material 306 may comprise one ormore side ports 370 similar to the side ports 161 through which a secondcatheter or other interventional device may be passed through to accessa surgical site. The side port 370 may be collapsible and closeable sothat no emboli passed through the side port 370 when it is not beingused. Alternatively, the porous mesh material 306 and the stent-likesupport structure 345 may be resilient enough so that a second catheteror other interventional device may be passed through its pores to accessa surgical site without permanently affecting the pore sizes of theaforementioned structures.

The embolic protection element 305 may be constructed with the porousmesh material 306 and the stent-like support structure 345 havingapproximately the relative longitudinal dimensions shown in 3D.Alternatively, the porous mesh material 306 and the stent-like supportstructure 345 can each be made longer or shorter without adverselyaffecting the performance of the embolic protection element 305. Inalternative embodiments, the stent-like support structure 345 can bemade slightly conical with the larger end of the cone on the upstream orproximal side.

The entire embolic protection element 305 or a portion of it may becoated with an anti-thrombogenic coating, for example, a bonded heparincoating, to reduce the formation of clots that could become potentialemboli. Alternatively or in addition, the embolic protection device 305or a portion of it may have a drug-eluting coating containing ananti-inflammatory or antistenosis agent. The embolic protection element305 can also be used for embolic protection of other organ systems. Forexample, the embolic protection element 305 can be deployed in thepatient's descending aorta for preventing embolic particles in theaortic blood flow from entering the renal arteries and embolizing in thepatient's kidneys. Alternatively or in addition, the entire sheath 300or portions of it may be radiopaque to facilitate viewing of the sheath300 as a procedure proceeds. Radiopaque markers may also be coupled toone or more portions of the sheath 300.

While preferred embodiments of the present invention have been shown anddescribed herein, it will be obvious to those skilled in the art thatsuch embodiments are provided by way of example only. Numerousvariations, changes, and substitutions will now occur to those skilledin the art without departing from the invention. It should be understoodthat various alternatives to the embodiments of the invention describedherein may be employed in practicing the invention. It is intended thatthe following claims define the scope of the invention and that methodsand structures within the scope of these claims and their equivalents becovered thereby.

What is claimed is:
 1. A method for introducing a catheter through anaccess sheath having integrated embolic protection, said methodcomprising: positioning the access sheath in a blood vessel with an opendistal end of the access sheath directed against the direction of bloodflow; deploying an embolic filter about the open distal end of theaccess sheath, wherein a cylindrical outer portion of the embolic filtercontacts a wall of the blood vessel and a conical inner portion definesa collection chamber between an inner surface of the cylindrical outerportion and an outer surface of the conical inner portion, wherein theconical inner portion is oriented to collect emboli in the blood in thecollection chamber; and introducing a catheter through a lumen of theaccess sheath while the embolic filter remains deployed about the opendistal end of the access sheath.
 2. A method as in claim 1, wherein theaccess sheath is positioned through a tubular outer delivery sheath thatmaintains the embolic filter in an undeployed retracted condition whenthe embolic filter is therewithin, and wherein the embolic filterdeploys into the deployed expanded configuration when the embolic filteris advanced out of the tubular outer delivery sheath.
 3. A method as inclaim 1, wherein the blood vessel is the aorta.
 4. A method as in claim3, wherein the cylindrical outer portion of the embolic filter coversthe ostia of the cerebral arteries of the aortic arch.
 5. A method as inclaim 1, wherein a distal end of the conical inner portion of the filteris fixedly attached to the open distal end of the access sheath and adistal end of the cylindrical outer portion of the filter is open andfree of attachment to the access sheath.
 6. A method as in claim 5, theconical inner portion is positioned inside the cylindrical outer portionand has a wider proximal end joined to the cylindrical outer portion. 7.A method as in claim 6, wherein a distal end of the embolic filter isopen for blood to flow between the conical inner portion and thecylindrical outer portion, with a space between the conical innerportion and the cylindrical outer portion defining the collectionchamber for captured emboli.
 8. A method as in claim 1, furthercomprising deploying a stent-like support scaffold about the cylindricalouter portion of the filter for supporting the cylindrical outerportion.
 9. A method as in claim 1, wherein the deploying the embolicfilter comprises releasing the embolic filter from constraint to allowthe embolic filter to self-expand.
 10. A method as in claim 1, furthercomprising pulling on a graspable structure to close the distal end ofthe cylindrical outer portion and seal the collection chamber.
 11. Amethod as in claim 10, further comprising withdrawing the filter fromthe blood vessel after the distal end of the cylindrical outer portionhas been closed.
 12. A method as in claim 1, further comprisingintroducing a second catheter, guide-wire, delivery sheath, or othersurgical tool through a closeable access port in the filter.
 13. Amethod as in claim 1, further comprising performing at least one of avalve replacement, balloon valvuloplasty, and blood vessel ablation withthe catheter that has been introduced.
 14. A method for introducing acatheter through an access sheath having integrated embolic protection,said method comprising: positioning the access sheath in a blood vesselwith an open distal end of the access sheath directed against thedirection of blood flow; deploying an embolic filter about the opendistal end of the access sheath, wherein a cylindrical outer portion ofthe embolic filter contacts a wall of the blood vessel and a conicalinner portion defines a collection chamber between an inner surface ofthe cylindrical outer portion and an outer surface of the conical innerportion, wherein the conical inner portion is oriented to collect emboliin the blood in the collection chamber; and introducing a catheterthrough a lumen of the access sheath while the embolic filter remainsdeployed about the open distal end of the access sheath; and wherein adistal end of the conical inner portion of the filter is fixedlyattached to the open distal end of the access sheath and a distal end ofthe cylindrical outer portion of the filter is open and free ofattachment to the access sheath.
 15. A method as in claim 14, theconical inner portion is positioned inside the cylindrical outer portionand has a wider proximal end joined to the cylindrical outer portion.16. A method as in claim 15, wherein a distal end of the embolic filteris open for blood to flow between the conical inner portion and thecylindrical outer portion, with a space between the conical innerportion and the cylindrical outer portion defining the collectionchamber for captured emboli.